This invention relates to a fluid circulation conduit, of very large transversal section, liable to exceed 2 m2, which can be buried under an embankment and more particularly intended for the circulation of fluid under high pressure, in the order of several bars.
A fluid transportation conduit can be made simply in the form of metal or concrete pipe elements, butt jointed and having ends inserted into one another, with interposed joints. In case of sinking, some elements may come loose and therefore, to resist relatively high pressures, it is preferable to use metal pipes whose elements are welded at their adjacent ends, for instance, in the case of forced conduit for hydro-electrical plants.
In such a case, the conduit is composed of prefabricated pipe elements or of curved panels, which are transported to the site and welded there. At that point; however, the pipe is not under pressure and may deform while taking an oval shape, which makes welding more difficult since the sheets would no longer be aligned.
Besides, such pipes must often be buried, for instance in the case of pipelines or gas-lines. When the pipe is under pressure, it can easily sustain the loads applied externally by the embankment. But the pressure may vary and even become negative with respect to the outside. There is then a high risk of deformation of the pipe.
For all these reasons, the pipes made by welding metal elements generally have a relatively limited section, most often smaller than 2 m2.
The present invention is intended to produce conduits for the transportation of fluid under pressure which do not exhibit such shortcomings.
With such a technique, the conduit is composed of a sealed thin-walled pipe, normally a metal pipe, fastened to a rigid supporting body, usually made of reinforced concrete or preloaded concrete. Thus, the metal pipe enables the system to be sealed and to resist the internal pressure, the thin wall being solely subjected to traction stresses, while the concrete body makes the conduit rigid while bearing upon the laying surface on a widened surface which distributes the loads applied and better resists differential sinking.
In the technique described in parent U.S. patent application Ser. No. 08/765,422 filed Jun. 28, 1995, now U.S. Pat. No. 5,904,185, the concrete supporting body consists advantageously of three sections, respectively a horizontal base bearing on the ground and two lateral bearing parts forming vertical legs along each side of the pipe, whereby the assembly exhibits a U-shaped profile completely surrounding the lower section of the pipe. The pipe therefore consists, as a straight section, of four panels, respectively a lower panel applied onto the base, two lateral panels applied respectively onto both lateral legs and an upper panel with two lateral edges which connect tangentially to the corresponding ends of two side panels. The side panels are held by both legs of the supporting body and their opposite edges can thus be perfectly aligned for welding purposes.
Such a conduit can be made easily from prefabricated elements whose length is compatible with the transportation and handling capacities.
The invention further in simplifies the production technique of such a conduit, in particular to make the various prefabricated elements lighter and to facilitate their installation, while retaining the various advantages provided by the prior.
The invention relates generally to a fluid circulation conduit, of large transversal section, in excess of 2 m2, comprising a pipe having a longitudinal axis and fixed on a rigid supporting body bearing on a laying surface. The pipe forms a sealed tubular enclosure constituted of a plurality of juxtaposed than walled panels and comprising a lower part having a U-shaped profile with two sides and an upper part, the supporting body comprising a horizontal base with a lower plane face bearing on the laying surface and two lateral wings extending vertically along the sides of the lower part of the tubular enclosure. The supporting body comprises, on either side of the tubular enclosure, a single-piece portion having, in cross-section, an L-shaped profile comprising a substantially vertical branch forming a lateral wing of the supporting body extending along the corresponding side of the lower part of the pipe and a substantially horizontal branch extending beneath the lower part of the pipe and forming at least a portion of the base of the supporting body resting on the laying surface.
Particularly advantageously, at least over a certain length of the pipe, both lateral wings and the base of the supporting body form a unitary piece.
According to another embodiment, at least over a certain length of the pipe, the supporting body comprises two L-shaped profile pieces whose horizontal branches connect on either side of the median plane of the pipe passing through the longitudinal axis, so as to form a continuous base.
Normally, the supporting body is made of reinforced concrete and the reinforcement can be made conventionally to sustain the loads applied, in particular, loads tending to spread the lateral sections apart. However, according to another particularly advantageous feature, the reinforcement may be made of at least one curved sheet, embedded in the concrete supporting body and having two branches, respectively horizontal and vertical, each into the corresponding branch of each L-shaped portion of the supporting body.
Preferably, to ensure transmission continuity of the loads, each L-shaped lateral part of the supporting body comprises an internal face for application and fixation of the enclosure, whose orientation varies gradually between a substantially horizontal lower section and a substantially vertical upper section.
The invention will be understood better by the following description of certain embodiments given by way of example and shown in the appended drawings.